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3/4" or 1" Backflow

I am curious if I can use a 3/4" backflow on my system or should I use a 1". I am tapping in right after the meter in my house (3/4"). My thought was to use 3/4" copper to span the 17' to the outside of my house, then either convert to 1" copper and install a 1" Febco, or keep the 3/4" copper and go to a 3/4" backflow, then out of the backflow size up to my 1" poly main line. What are the pros and cons of 1" backflow vs. 3/4. I want to go the best route possible, both economical and performance.

I have fixed many backflow devices that are too small in pipe size. I would use 1" copper from your copper mainline up to your backflow device, then use PVC pipe for your sprinkler mainline. Do not use poly for your mainline. It cannot withstand the constant pressure that mainlines hold. Hope this helps and good luck!!

I would use 1" (much better) after the backflow use PVC (schedule 40) right to your control valves. Remember to put the PVB in a garden out of the way 12" above ground and OUTSIDE. The Double checks can go in the ground or inside.